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ISO/TR 25088 — Guidance for the Application of Low-Carbon Technologies in Steel Plants
Comprehensive Technical Reference for Steel Industry Decarbonization Across Smelting, Process Optimization, Resource Recycling, and CCU Pathways
1. Introduction to Low-Carbon Technologies in the Iron and Steel Industry
ISO/TR 25088:2026, prepared by ISO/TC 17/SC 21 (Steel — Environment related to climate change in the iron and steel industry), provides comprehensive guidance for the application of low-carbon technologies across the entire iron and steel production process. With the intensification of global actions to address climate change, the steel industry — responsible for approximately 7-9% of global CO2 emissions — faces unprecedented pressure to achieve low-carbon transformation through technological innovation and industrial upgrading.
This Technical Report classifies low-carbon technologies into four main categories: smelting process breakthroughs, process optimization and innovation, resource recycling, and CO2 capture and utilization. For each technology, the document evaluates technical sophistication, feasibility, technology maturity, and application conditions, providing steel enterprises with a systematic framework for selecting technologies suited to their specific conditions.
The steel industry’s decarbonization challenge is particularly acute because approximately 70% of its emissions come from the chemical reduction of iron ore — a process that inherently produces CO2 regardless of the energy source used. This makes traditional energy efficiency improvements insufficient; breakthrough technologies are essential.
2. Technology Classification and Technical Properties
ISO/TR 25088 organizes low-carbon technologies into a structured classification with detailed technical property assessments.
| Category | Technology | Process Stage | Maturity | Key Challenge |
|---|---|---|---|---|
| Smelting Breakthrough | Hydrocarbon coupling enhanced blast furnace | Ironmaking | Emerging | Insufficient hydrogen-rich gas |
| Smelting Breakthrough | Hydrogen-based direct reduction (H2-DRI) | Ironmaking | Emerging | Green H2 availability, cost |
| Smelting Breakthrough | Low-carbon sintering in stratified heating | Sintering | Emerging | Technology integration |
| Smelting Breakthrough | Near-zero CO2 EAF steelmaking | Steelmaking | Established | Scrap availability, grid decarbonization |
| Process Optimization | Near net shape rolling | Rolling | Established | Product mix limitations |
| Process Optimization | High pellet ratio ironmaking | Ironmaking | Established | High-grade ore supply |
| Resource Recycling | High scrap ratio BOF smelting | Steelmaking | Emerging | Excessive cost, scrap quality |
| Resource Recycling | Top pressure recovery turbine (TRT) | Ironmaking | Established | — |
| Resource Recycling | Coke dry quenching (CDQ) | Cokemaking | Established | — |
| CCU | CO2 injection in BOF | Steelmaking | Established | Market demand |
| CCU | CO2 mineralization via steel slag | Steelmaking | Emerging | Production cost |
2.1 Hydrogen-Based Direct Reduction — The Game Changer
Among the breakthrough technologies, hydrogen-based direct reduction (H2-DRI) combined with electric arc furnace (EAF) steelmaking represents the most promising pathway to near-zero emissions steel production. The process replaces fossil carbon (coke and coal) with green hydrogen as the reducing agent, producing water vapour instead of CO2 as the by-product. However, the document notes that this technology requires massive quantities of green hydrogen — approximately 600 kg of H2 per tonne of steel — and the current global electrolysis capacity is orders of magnitude below what would be required for widespread adoption.
The maturity assessment in ISO/TR 25088 reveals an important reality: most breakthrough technologies are still in the emerging or R&D stage. Established technologies (EAF, TRT, CDQ, near net shape rolling) provide incremental improvements, but the transformational change required for deep decarbonization will depend on technologies that are not yet commercially mature.
3. Engineering Design Insights: Implementation Guidance
ISO/TR 25088 provides practical guidance for steel enterprises developing their low-carbon roadmaps:
3.1 Technology Selection Framework
The document’s classification system enables enterprises to map their current production configuration against available low-carbon technologies. An integrated steel mill with blast furnaces should prioritize near-term process optimization (high pellet ratio, CDQ, TRT) while investing in pilot projects for hydrogen injection and CCU. A scrap-based EAF minimill, by contrast, has a different pathway focused on increasing scrap quality, adopting renewable electricity, and exploring CO2 mineralization using slag.
3.2 The Role of CCU in Steel Decarbonization
CO2 capture and utilization technologies address the fundamental challenge that even with energy efficiency improvements and fuel switching, some process emissions from iron ore reduction are unavoidable. CCU technologies — including CO2 injection into the basic oxygen furnace (BOF) to produce synthetic fuels, and CO2 mineralization using steel slag to produce construction materials — offer pathways to capture and utilize these residual emissions. The document notes that CO2 mineralization using steel slag has the dual benefit of carbon capture and slag valorisation.
3.3 Economic Considerations
While ISO/TR 25088 is primarily a technical document, it acknowledges that economic aspects must be taken into account for meaningful technology adoption. The cost of green hydrogen, carbon pricing mechanisms, electricity grid decarbonization rates, and scrap availability all influence the business case for each technology. Enterprises are encouraged to develop site-specific decarbonization roadmaps that account for local conditions.
For steel industry engineers and sustainability professionals, ISO/TR 25088 serves as a comprehensive reference: it maps the entire technology landscape, provides maturity assessments, and offers a structured framework for developing enterprise-specific low-carbon transformation strategies aligned with global climate goals.
4. Frequently Asked Questions
Q1: What is the difference between low-carbon technology and best available technology (BAT)?
Low-carbon technologies specifically target greenhouse gas emission reductions. BAT documents (e.g., EU BREF) cover a broader set of environmental impacts. The document explicitly includes BAT as a subset of low-carbon technologies.
Low-carbon technologies specifically target greenhouse gas emission reductions. BAT documents (e.g., EU BREF) cover a broader set of environmental impacts. The document explicitly includes BAT as a subset of low-carbon technologies.
Q2: Can carbon capture and storage (CCS) be applied to steel plants?
The document focuses on CCU (utilization) rather than CCS (storage). However, CO2 capture technology is listed as a key enabling technology, and the captured CO2 can theoretically be either utilized or stored depending on local geological conditions and regulatory frameworks.
The document focuses on CCU (utilization) rather than CCS (storage). However, CO2 capture technology is listed as a key enabling technology, and the captured CO2 can theoretically be either utilized or stored depending on local geological conditions and regulatory frameworks.
Q3: How does technology maturity affect the guidance?
Technologies are classified as established (broad application), emerging (few isolated applications), or R&D (lab scale). The document will be revised as technologies evolve, providing updated guidance as maturing technologies become commercially viable.
Technologies are classified as established (broad application), emerging (few isolated applications), or R&D (lab scale). The document will be revised as technologies evolve, providing updated guidance as maturing technologies become commercially viable.
Q4: Is this document applicable to all steel production routes?
Yes. The document covers the entire production chain — sintering, pelletizing, coking, ironmaking, steelmaking, continuous casting, and rolling — making it applicable to integrated BF-BOF mills, DRI-EAF plants, and scrap-based EAF minimills.
Yes. The document covers the entire production chain — sintering, pelletizing, coking, ironmaking, steelmaking, continuous casting, and rolling — making it applicable to integrated BF-BOF mills, DRI-EAF plants, and scrap-based EAF minimills.
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